The ASD biological cascade identifies several upstream biological channels that can drive downstream learning disruption, synapse instability, stress signaling, and behavioral expression. At the individual level, however, one or two channels usually dominate first. Testing exists to identify which channels are most active in the child in front of you, so the next steps are sequenced around the likely driver rather than applied generically.
This page is the entry point for the majority of users. It is designed to answer one practical question: what should we investigate first, based on what we are actually seeing?
How to use this section
Start with the symptom branch that best matches the child’s current presentation. Most children will overlap more than one branch. Use that overlap to prioritize the first round of testing rather than trying to run every possible panel at once.
Skill loss / regression is a different pathway
If a child has lost previously acquired speech, motor, social, or adaptive skills, that is a different biological presentation with a modified testing priority. See: Skill Loss / Regressive Autism: Testing Pathway.
For biological context around immune-trigger questions, see The Vaccine Question.
Most likely emphasis: gut dysbiosis, barrier disruption, LPS signaling, SST effects on digestion.
- Start with OAT for dysbiosis markers and metabolic overlap.
- Add stool testing when symptoms are persistent or severe.
- Add Zonulin and LBP when gut barrier disruption or immune spillover is suspected.
- Use pancreatic elastase and stool inflammation markers when digestion and mucosal strain seem prominent.
Most likely emphasis: immune activation, neuroinflammation, IDO1 pressure, excitatory signaling.
- Start with Kynurenine / Tryptophan ratio or downstream OAT proxies.
- Add hsCRP, cytokines, and related inflammatory markers.
- Consider BDNF as a downstream tracking marker rather than an initial routing marker.
Most likely emphasis: HPA axis dysregulation, SST load, cortisol rhythm disruption.
- Start with salivary cortisol rhythm or an equivalent diurnal stress panel.
- Add IGF-1 and related markers when SST signaling burden is part of the question.
- Use this branch especially when sleep and sensory patterns are persistent rather than situational.
Most likely emphasis: mitochondrial dysfunction, TCA cycle blockade, ATP strain.
- Start with OAT TCA cycle markers.
- Add lactate:pyruvate when respiratory chain dysfunction is suspected.
- Add carnitine profile and CoQ10 when first-line findings support mitochondrial strain.
Most likely emphasis: toxic burden, oxidative strain, multisystem destabilization.
- Use environmental panels selectively rather than as universal first-line testing.
- Prioritize them when exposure history, geography, housing, or sudden worsening supports the question.
When budget or access is limited, a smaller first panel can still provide directional value.
| Test | Why it matters |
|---|---|
| OAT | Broadest overlap across gut, mitochondrial, and kynurenine-related pathways. |
| CBC / CMP | Basic physiological context and screening baseline. |
| hsCRP | Accessible inflammatory signal. |
| Vitamin D | Common low-support marker with relevance to immune tone. |
Most children present across several of these branches simultaneously — GI symptoms, behavioral escalation, and sleep disruption often appear together because they share upstream drivers. Work through every branch that applies. The first-line panel in Section 3 will tell you which channels are most active so you can prioritize.
- First test to order: OAT (Organic Acids Test, full panel). Checks dysbiosis metabolites including arabinose (yeast) and HPHPA (Clostridia) in a single urine collection — highest-yield first test for this channel.
- If OAT dysbiosis markers are elevated: Add GI-MAP comprehensive stool analysis (Diagnostic Solutions). Confirms pathogen load, calprotectin (gut inflammation), and pancreatic elastase (enzyme output). Do not start probiotics until this picture is clear.
- If GI symptoms persist with normal OAT: Add Zonulin + LPS-Binding Protein (LBP). These directly measure active gut barrier disruption and LPS translocation — which can occur even without dramatic OAT dysbiosis findings.
- If GI-MAP elastase is low: SST is inhibiting pancreatic enzyme secretion. The SST/HPA channel is co-active — add salivary cortisol (4-point) and IGF-1 from Branch C.
- Protocol implication: Active gut channel confirmed → gut repair becomes Layer 1 before all other interventions. Systemic layers underperform while LPS continuously re-triggers NF-κB.
- First tests to order: OAT (full panel) focusing on kynurenine metabolites — quinolinic acid elevated with kynurenic acid low signals IDO1 maximally activated, tryptophan diverted, SIRT1 fuel depleted. Also order hsCRP as an accessible systemic inflammatory marker.
- If OAT quinolinic acid is elevated + hsCRP is elevated: Add Kynurenine/Tryptophan (K:T) ratio and cytokine panel (IL-6, TNF-α). K:T elevated confirms IDO1 actively diverting tryptophan. Both results together → NMN/NR + luteolin + omega-3 move to Layer 1 immediately.
- If cytokines are elevated but K:T is normal: Non-IDO1 inflammatory trigger. Add GPL-TOX (environmental toxins) and Zonulin + LBP — the trigger may be environmental or gut-driven rather than kynurenine-pathway-driven.
- Protocol implication: IDO1 and M1 microglia both active → NMN/NR + luteolin + omega-3 all move to Layer 1. NAC added urgently if quinolinic acid is elevated.
- First tests to order: Salivary cortisol (4-point diurnal curve, ZRT or DUTCH) + serum IGF-1 + fasting insulin. Order as a set — they give complementary pictures of HPA dysregulation and functional SST load.
- If cortisol curve is flat or inverted: HPA axis dysregulated; SST is tonically elevated. Sleep and circadian optimization become non-negotiable Layer 1 — melatonin timing is the most urgent single intervention.
- If IGF-1 is low for age + cortisol curve is abnormal: SST doubly confirmed via two independent pathways (HPA and GH suppression). Layer 5 SST interventions move to Layer 2.
- If DHEA-S is low + cortisol curve is flat: HPA exhaustion pattern confirmed. Adrenal recovery must precede SIRT1 restoration. Reduce all HPA stressors before advancing the protocol.
- Add hair cortisol (3-month integrated) to distinguish chronic HPA load from a transient spike — especially useful when salivary cortisol shows a borderline pattern.
- Protocol implication: SST/HPA channel active → sleep and circadian optimization is Layer 1, no exceptions. BDNF baseline confirms CREB suppression and sets treatment response tracking.
- First test: OAT (full panel) — TCA cycle markers (succinic, fumaric, malic acids). Elevated TCA intermediates confirm mitochondrial block. The most accessible first screen for this channel.
- If two or more TCA markers are elevated: Add plasma lactate:pyruvate ratio + full carnitine panel. Ratio >20 at rest confirms respiratory chain dysfunction. Acylcarnitine profile identifies specific metabolic blocks.
- Add plasma CoQ10 when TCA markers are elevated — CoQ10 deficiency is common in mitochondrial dysfunction and directly addressable with ubiquinol supplementation.
- Protocol implication: Mitochondrial channel confirmed → CoQ10 ubiquinol + NMN/NR move to Layer 1 alongside magnesium. L-carnitine added if deficient on panel.
- This branch is different from A–E: You don't observe environmental burden the way you observe a meltdown or a sleep problem. You suspect it based on where you live, what your child eats, or your water source. Order this channel investigation based on exposure history rather than presenting symptoms.
- First tests to order: GPL-TOX (Great Plains Laboratory, urine) screens 172+ environmental chemicals including glyphosate and organophosphates. RBC heavy metals (mercury, lead, arsenic, cadmium) — specify RBC, not serum, for chronic tissue exposure rather than recent exposure.
- If glyphosate is elevated: Gut microbiome disruption is compounded — glyphosate depletes the same Lactobacillus and Bifidobacterium species already compromised in ASD. Gut repair becomes more urgent alongside detox support.
- If metals are elevated: NAC + glutathione support urgently before other antioxidant layers. Professional chelation consultation if mercury or lead is significantly elevated. SIRT1 cannot be restored while heavy metal burden suppresses it directly.
- Add GSH:GSSG ratio when environmental burden is confirmed — this quantifies antioxidant depletion depth and whether NAC alone is sufficient or direct glutathione support is needed.
- Protocol implication: Environmental channel active → detox support sub-layer added before Layer 1. NAC becomes co-foundational. Reducing ongoing exposure is prerequisite — supplementation alone cannot overcome continuous toxin input.
Why standard labs come first
Before ordering specialty panels like the OAT or GI-MAP, a standard first-line draw through your primary care physician or a direct-to-consumer lab gives you directional channel data at a fraction of the time and complexity. These tests are universally available, covered by most insurance, and ordered without specialist referral. Positive findings tell you which specialty panels to prioritize next — and which channels you can deprioritize. Every family should start here regardless of what comes after.
| Channel | First-line test(s) | What it tells you | If positive — next step | Access |
|---|---|---|---|---|
| Gut / LPS | hsCRP + CBC differential | hsCRP >1.0 mg/L without acute infection = systemic inflammation consistent with LPS translocation. CBC monocytosis can reflect chronic gut-driven immune activation. | Gut repair layer elevated in priority. Order GI-MAP if hsCRP is elevated and GI symptoms are present. | LabCorp / Quest. Covered by most insurance. Often included in standard annual labs. |
| Mitochondrial | CMP (fasting) + serum lactate | Elevated lactate, low bicarbonate, or abnormal glucose flags metabolic strain. Serum lactate >2.0 mmol/L at rest flags mitochondrial dysfunction. | CoQ10 + NMN/NR elevated in priority. Add OAT TCA markers as confirmatory next step. | LabCorp / Quest standard. CMP covered universally. Request fasting draw. |
| MIA / Neuroinflammation | hsCRP + ESR | Both elevated without infection = chronic inflammatory state consistent with active neuroinflammation. Interpret jointly — neither alone is sufficient. | K:T ratio and cytokine panel (IL-6, TNF-α) are highest-yield next steps. Anti-inflammatory layer (luteolin, omega-3) becomes immediate priority. | LabCorp / Quest. Covered by most insurance. |
| SST / HPA Axis | Fasting insulin + IGF-1 + DHEA-S | Elevated fasting insulin = metabolic SST trigger. Low IGF-1 for age = functional SST excess. Low DHEA-S = HPA exhaustion. Any two of three abnormal = SST channel active. | Sleep and circadian optimization become Layer 1. Add salivary cortisol (4-point) for the full HPA picture. Low IGF-1 + low DHEA-S: SST doubly confirmed. | LabCorp / Quest standard. All three inexpensive and widely covered. Order as fasting draw. |
| Environmental / Oxidative | RBC heavy metals (Hg, Pb, As, Cd) + Vitamin D (25-OH-D) | RBC metals = most accessible chronic exposure screen. Vitamin D deficiency (<40 ng/mL) is near-universal in ASD and permits unchecked NF-κB activation. | Metals elevated: NAC + glutathione support urgent; add GPL-TOX. Vitamin D <40 ng/mL: D3 + K2 immediately regardless of all other findings. | LabCorp / Quest. Specify RBC (not serum) for metals. Order Vitamin D for every individual as a baseline. |
| Universal baseline | CBC + CMP + Vitamin D + hsCRP | Minimum baseline for every individual: systemic inflammation, metabolic strain, nutritional status, and renal/hepatic function — all of which amplify or constrain the cascade. | Any abnormality routes to channel-specific follow-up above. CRP elevated: anti-inflammatory layer becomes priority. Vitamin D <40: supplement immediately. | LabCorp / Quest. Covered universally. Available through primary care without specialist referral. |
What this panel covers and costs
CBC + CMP + Vitamin D + hsCRP + fasting insulin + IGF-1 + DHEA-S + RBC heavy metals: typically $150–$350 total through LabCorp/Quest at retail, often significantly less with insurance. This panel gives directional signal across all five channels before any specialty testing. Direct-to-consumer without physician referral: Ulta Lab Tests, Any Lab Test Now, LabCorp patient portal — available in most states.
Each channel has a confirmation threshold — a combination of findings that together confirm it is an active upstream driver, not a background signal. Use these cards after receiving results to determine whether a channel is confirmed and how the protocol should be reordered. For the full result-by-result interpretation table, see Document 07C.
Zonulin elevated + LBP elevated + OAT gut dysbiosis markers elevated. Any two of three in the same direction confirms the channel.
Protocol reorderGut repair becomes Layer 1. All systemic interventions have reduced efficacy while LPS continuously re-triggers NF-κB. Address gut before advancing other layers.
Two or more TCA intermediates elevated on OAT + lactate:pyruvate ratio >15 at rest.
Protocol reorderCoQ10 ubiquinol + NMN/NR move to Layer 1 alongside magnesium. L-carnitine added if deficient. Mitochondrial support precedes downstream neuroinflammation interventions.
Elevated K:T ratio + elevated IL-6 or TNF-α + elevated quinolinic acid on OAT. K:T alone is sufficient to begin the anti-inflammatory layer.
Protocol reorderNMN/NR + luteolin + omega-3 all move to Layer 1. NAC added urgently if quinolinic acid is elevated. Anti-inflammatory layer cannot wait for downstream steps.
Abnormal cortisol diurnal pattern + elevated hair cortisol + low IGF-1 for age. Any two of three confirm the channel.
Protocol reorderSleep and circadian optimization are non-negotiable Layer 1. Hair cortisol elevated = chronic HPA load confirmed, not transient. Low-dose forskolin only after HPA stabilization.
Multiple GPL-TOX positives or elevated RBC metals + low GSH:GSSG ratio + elevated 8-OHdG on OAT.
Protocol reorderDetox support sub-layer added before Layer 1. NAC becomes co-foundational. Ongoing exposure reduction is prerequisite — supplementation alone cannot overcome continuous toxin input.
Serum BDNF is the downstream output of the cAMP/PKA/CREB pathway — the convergence point of both the SST arm and the SIRT1 arm of the cascade.
How to use itOrder at baseline alongside first-line tests. Low BDNF confirms CREB suppression. Retest at 3 and 6 months — rising BDNF is the primary objective marker that the cascade is responding to the protocol.